This invention relates to an anchoring adhesive usefull in industrial or commercial construction applications such as bridges, highways, airports, skyscrapers, stadiums and tunnels. The anchoring adhesive maintains pins, hangars, bolts, rods, and other anchor devices firmly in place, in structural openings formed in concrete, masonry, metals (e.g., steel), ceramics, plastics, glass and wood.
Chemical anchoring adhesives are known which are composed of two or more components that react together and cure when mixed, U.S. Pat. No. 5,730,557, issued to Skupian et al., discloses a mortar mixture capsule unit for chemical attachment of anchors in boreholes. The capsule houses a filler material, and a chemical binder system contained in smaller capsules within the filler material. The cartridge is inserted into a borehole, and a driving tool is used to insert an anchor. The driving tool imparts motion to the anchor, which ruptures both the housing capsule and the smaller capsules contained within it, causing the chemical binder system to interact and mix with the filler. The interaction and mixing causes reaction and curing of the binder system/filler mixture, thereby securing the anchor within the borehole. A similar adhesive is sold by Hilti AG under the trade name xe2x80x9cHVUxe2x80x9d.
U.S. Pat. No. 5,731,366, issued to Moench et al., discloses a chemical plugging compound based on a free-radically polymerizable resin and a free-radical initiator spatially separated from the resin. The spatial separation can be effected by encapsulating the initiator in glass, gelatin or cellulose capsules. The plugging compound is described as being self-supporting and storage stable.
This and other prior art chemical anchoring adhesives have certain disadvantages. One disadvantage is that one or both components are fluid, and must be wrapped, encapsulated or otherwise enclosed in a package prior to use. Thus, it is not easy to vary the size of a capsule or the amount of adhesive capsule used in a borehole, while at the job site. Put another way, oversized and undersized boreholes will receive tile same amount of predetermined, pre-packaged adhesive as boreholes of standard size.
Another disadvantage is that the fluid adhesives may flow or spill from the boreholes during use, particularly after the package is ruptured by the anchor being driven. The problem is especially acute when the borehole is upside down and vertical, but also exists when the borehole is horizontal, or at an angle between horizontal and upside down vertical. Even when the adhesive is not completely fluid, the prior art cartridges are typically not self-retentive, i.e., the cartridges will fall from overhead boreholes.
Another disadvantage is that the two components, binder and filler, must be completely segregated prior to use, to prevent premature interaction and reaction. The encapsulation techniques used to accomplish this require some precision and expense. Also, there is no assurance that the smaller capsules used to contain the binder will remain evenly dispersed among the filler until the adhesive capsule is used. Uneven dispersion of the binder and filler can lead to uneven or inadequate reinforcement of the anchor.
Cartridge adhesives are another type of prior art adhesive. Cartridge adhesives include two separate parts which are simultaneously injected into a borehole using a two-barrel caulking gun which brings the two parts together at the point of injection, whereupon they react upon entering the borehole. Disadvantages of cartridge adhesives include excessive packaging waste, excessive adhesive waste due to unmixed, unused material remaining in the caulking barrels, and insufficient viscosity which permits the material to run out of vertical overhead boreholes, and to sag in horizontal boreholes.
The present invention is directed to an anchoring adhesive composition including two parts, both of which have a solid, putty-like consistency. The two parts can be joined side-by-side in a rope or other elongated configuration, without encapsulating one relative to the other. Put another way, the two parts, although joined together in a face-to-face relationship, will not significantly react with each other prior to insertion of the anchoring adhesive in a borehole.
The first part of the adhesive composition includes about 20-45% by weight of a liquid epoxy resin, about 10-40% by weight of a first particulate filler preferably comprising talc, and about 40-65% by weight of a second particulate filler preferably comprising silica.
The second part of the adhesive composition comprises about 5-20% by weight of an amine or chemical derivative thereof, about 0.1-15% by weight of a tertiary amine, about 1-23% by weight of a first particulate filler preferably comprising talc, and about 52-87% by weight of a second particulate filler preferably comprising silica.
The first and second parts can be extruded, pressed or otherwise joined together in the form of a rope having a cylindrical, rectangular, square, triangular, or other suitable shape. The rope may have any suitable cross-sectional diameter and shape, and may have any suitable length. The rope may be wrapped around its circumference using a suitable wrapper made of plastic, metal foil, paper, or the like.
The rope of anchoring adhesive composition may be cut or sheared to any size, depending on the depth of the bore. In one embodiment, the proper amount of adhesive can be measured by the depth of the borehole, i.e., by inserting a rope end into the borehole as far as possible, and cutting or shearing through the rope at the top of the borehole. If the boreholes vary in depth, the anchoring adhesive may be cut on the job site as needed, to provide the proper amount of adhesive to each borehole. Because the two parts are extruded side-by-side, and have flexible solid consistencies, the amount of each part present along a cross-section remains substantially consistent along the axial length of the rope. Because both parts have a solid phase consistency, the only direct contact between them prior to use is along a single interface. Thus, premature reaction between the two parts is minimized without requiring encapsulation of one or both parts.
With the foregoing in mind, it is a feature and advantage of the invention to provide a two-part anchoring adhesive composition having a consistent composition along its axial length, which provides consistent high-quality anchoring force in heavy construction for commercial and residential applications.
It is also a feature and advantage of the invention to provide a two-part anchoring adhesive which is easy and inexpensive to manufacture, and does not require separate encapsulation of one or both parts.
It is also a feature and advantage of the invention to provide a two-part anchoring adhesive which has a solid, putty-like consistency, and which can be cut to any desired length on the job site, or before reaching the job site.
The foregoing and other features and advantages will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings and examples. The detailed description, drawings and examples are illustrative rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof.